1. Field of the Invention
The present disclosure relates generally to the design of equipment chassis such as a network chassis, and more specifically, to improved air flow and cooling techniques for network chassis.
2. Description of the Related Art
Networked communication systems typically include various hardware components such as network chassis (and sub-components) that support the overall network functionality. These various hardware components generate large amounts of heat, which is typically removed continuously to prevent resident electronic components from reaching elevated temperatures, resulting in degraded performance, damage, or even failure. Conventionally, the heat is removed by, for example, forced convection airflow through or around the heat producing electronic components.
A conventional networking chassis typically includes sub-components such as network circuit boards or line cards, which contain circuits and the external interface connectors, and fabric cards, which contain switching circuits for connecting line cards. To achieve the highest degree of connectivity between line cards and fabric cards; high-performance network switches use an orthogonal mid-plane design where the line cards are oriented in one direction (either horizontal or vertically) and are inserted into the mid-plane from the front of the chassis, while the fabric cards are oriented in a direction orthogonal to the line cards and are inserted into the mid-plane from the rear of the chassis.
Conventionally, orthogonal chassis designs typically use one of two methods of cooling. The first method uses multiple airflow paths to cool each set of cards—e.g., horizontal line cards can be cooled using side-to-side airflow, while vertical cards are cooled using separate blowers. However, such side-to-side chassis airflow requires cooler air entry on sides of each network chassis, which may not be supported for certain data center designs (e.g., limited space available). The second method uses front to rear cooling where air enters through air intake holes in the faceplates of front boards. In most applications, the face plate is covered by many connectors that restrict the location and number of the holes which in turn causes difficulties with the delivery of air to the parts of the circuit that most need it. The second method fails to consider air filtering requirements for certain network applications (e.g., telecommunications networks).
Accordingly, there remains a need for a space efficient network chassis that satisfies the heat dissipation requirements for the various sub-components in an orthogonal configuration and also satisfies the air filtering requirements for certain network applications.